This story has been updated.
The extraordinary turnout was the latest evidence that Sanders, 73, has tapped into the economic anxiety of the Democratic electorate. In recent weeks, his crowds have swelled, and his poll numbers have been on the rise, particularly in New Hampshire, the nation’s first primary state.
Sanders touched on familiar themes during his speech, which was streamed live on social media sites Saturday night. He called the nation’s current minimum wage of $7.25 “a starvation wage.” He lamented that the United States does not guarantee medical leave and vacation time. He derided a trade deal being pushed by President Obama, and he urged that more be done to combat climate change.
Sanders's audience -- in a state not among those with traditional early nominating contests -- rivaled the largest drawn by Clinton and the Vermont senator in recent weeks.
Clinton’s team put the crowd at about 5,500 a week ago when she held a rally at New York City’s Roosevelt Island that was billed as the formal launch of her campaign. An estimated 5,000 supporters streamed to Sanders’s hometown kickoff in Burlington, Vt., in late May. And a few days later, Sanders drew a reported crowd of close to 3,000 in Minneapolis.
Before he took the stage, Sanders’s audience in Denver was treated to a selection of recorded songs by classic rocker Neil Young. Earlier this week, Republican contender Donald Trump used a Young song, “Rockin’ in the Free World,” as he came on stage for his announcement. That drew a rebuke from Young, a Canadian citizen who said he is supporting Sanders.
The crowd count of 5,500 for Saturday's event was provided by University of Denver officials. During the event, the university estimated the crowd to be 4,500 people, a figure that was included in a Sanders campaign news release. After the event, the estimate was raised to account for additional people gathered on the lacrosse field.